Powders are a complex mixture of solid particles and/or granules interspersed with air. The powder form is often useful. For example, from an application perspective, powders are less labor intensive to handle and are easier and more accurately measured than are other forms of solid materials e.g., solid blocks. Free-flowing powders are easily mixed and blended and facilitate the handling and packaging of a product on the commercial scale.
As is well known in the art, starch, in its native form, is a free flowing powder. The native starch powder is comprised of solid particles of starch that are typically of a size that is between about 4 μm and 100 μm, and have an average density of about 1.4 g/cm3. Starch is an abundant, useful, and inexpensive natural biodegradable material. In the form of a free-flowing powder, starch is easy to handle and package on a commercial scale. Free-flowing starch powders can also be easily mixed and blended with other powders.
Starch powders are potentially useful carrier agents. As noted above, starch is edible and biodegradable. Thus, because it is also abundant and inexpensive, it is ideal for applications that require a carrier agent to be edible and/or biodegradable. Unfortunately however, native starch powders have only a limited ability to function as carrier agents, particularly for liquid substances.
Indeed, only thin film of liquid can be formed around each individual starch granule when the native starch powder is mixed with a non-aqueous liquid e.g., an oil. Thus, only a small percentage of the oil can be loaded onto the starch powder before the flow properties begin to change. Loading more than about 5% oil (weight basis) onto native starch powder markedly affects the flowability and dispersion of the starch. In fact, loading more than 5% oil leads to agglomeration of the starch granules.
As noted above, native starch powder typically comprises particles that are in a size range from about 4 μm to about 100 μm. However, the range of potential applications for which starch is useful would be extended if smaller particle sizes were available. An exemplary application is in the plastics industry. Another exemplary application is in the beekeeping industry. Other exemplary applications are found, but not limited to the pharmaceutical industry and the fragrance industry.
Thus, there exists a need in the art for free flowing powders comprising small starch particles and for free flowing small starch particles loaded with substantial quantities of non-aqueous liquid. Fortunately, as will be clear from the following disclosure, the present invention provides for this and other needs.